EXECUTIVE SUMMARY

The findings of the East Kleinemonde Intermediate Ecological Reserve Determination Study are presented.The study was undertaken for the Resource Directed Measures Chief Directorate, Department of WaterAffairs and Forestry (DWAF) as part of a Water Research Commission project (K5/1581) on temporarilyopen/closed estuaries in the Eastern and Western Cape Provinces.

The East Kleinemonde Estuary is situated approximately 15 km north east of Port Alfred- The estuary issmall, shallow {1-2 m depth), approximately 120 m across at its widest section near the mouth, and has asurface area of approximately 25 ha when closed. During periods of extended mouth closure the water levelcan rise to about 2.3 m MSL and extensive back flooding occurs as a result of the formation of a sand bermacross the mouth. However, after the mouth has opened, the estuary is very shallow with a maximum depthof approximately 1 m.

Key findings of the study• Appendix A• Appendix B• Appendix C• Appendix D• Appendix E• Appendix F• Appendix G• Appendix H• Appendix I• Appendix J• Appendix K• Appendix L

are summarised in the appendices to the main report:Availability of data on the East Kleinemonde EstuarySpecialist report: Simulated catchment hydrologySpecialist report: Physical dynamicsSpecialist report: Coastal processes and sediment dynamicsSpecialist report: Water qualitySpecialist report: MicroalgaeSpecialist report: MacrophytesSpecialist report: MacrobenthosSpecialist report: Zooplankton and hyperbenthosSpecialist report: FishSpecialist report: BirdsProposed changes to RDM methodology for estuaries

Project Team

The core specialist team responsible (component leaders indicated in bold typing) for RDM templates andattending the specialist workshop (18-19 April 2007 in Port Elizabeth) is as follows:

Role/Expertise

Workshop coordination.Report preparation andHydrodynamics

Water quality

Sediment dynamics

Microalgae

Estuarine vegetation

Invertebrates

Fish

Birds

Lead specialists

Ms Lara van Niekerk

Ms Susan Taljaard*

Mr Andre Theron*

Dr Phumelele Gama

Prof Guy Bate

Prof Janine Adams

Prof Tris Wooldridge

Contact details

CSIR. Stellenbosch. lvnieker(S)csir.co za

CSIR, Stellenbosch, sta!jaar(5)csir.co za

CSIR, Stellenbosch. atheron(5>csir.co.za

Nelson Mandela Metropolitan University,phumelele. qama(a)nmmu.ac.za

Diatom and Environmental Management,bateq(5>netfocus.co.za

Nelson Mandela Metropolitan University,ianine.adams(5>nmmu. ac.za

Nelson Mandela Metropolitan University,tris. woold ridqe(5)nmmu.ac.za

Prof William Froneman* Rhodes University. W.Froneman{S)ru.ac.za

Dr Paul Cowley

Dr Alan Whitfield

Dr JaneTurpie

South African Institute of Aquatic Biodiversity.P.Cowley@ru.ac.za

South African Institute of Aquatic Biodiversity.A.Whitfield(3>ru ac.za

Anchor Environnemental Consultants,jane.turpie(5)botzoo.uct.ac.za

Did not attend RDM specialists workshop

The following persons formed part of the project team to support capacity building in the applicationEcological Reserve determinations on estuaries:

of

Person

Mr Gavin Snow

Ms Taryn Riddin

Dr Thomas Bornman

Mr Steve Lamberth

Mr Lukhanyiso Vumazonke

Dr Nadine Strydom

Ms Nicola James

Ms Anja Terbrde

Role/ expertise

Microalgae

Estuarine vegetation

Estuanne vegetation

Fish

Invertebrates

Ichthyoplankton

Fish

Birds

Contact details

Nelson Mandela Metropolitan University,aavin snow(S)nmmu.ac za

Nelson Mandela Metropolitan University,triddin(S)isat co.za

Nelson Mandela Metropolitan University.tom.bornman(<i)nmmu ac.za

Marine and Coastal Management, DEATl_amberth(5)deat qov.za

South African Institute of Aquatic Biodiversity,1 vumazonke(S)ru ac.za

South African Institute of Aquatic Biodiversity,N.Strvdom(a)ru.ac za

SAEON Elwandie Node.nikkij(5)saeon ac za

University of Cape Town.Anjater(5)vahoo.de

Other parties present at the Estuarine Specialist Workshop, held in Port Elizabeth on 18 and 19 April 2007:

PersonMs Barbara Weston

Ms Fiona Mackay

Prof AT Forbes

Ms Nicolette Demetnades

Affiliation/rote

RDM Directorate, DWAF

Oceanographic Research Institute

Marine and Estuarine Research

Marine and Estuarine Research

Contact detailsweston b(®dwaf. qov.za

fmackav(5)on orq

tickv(5)mer. co.za

nicolette®mer co za

Overview of the Process on the Determination of the Ecological Reserve for Estuaries

The preliminary determination of the Ecological Reserve can be conducted on different levels, namely:

• Comprehensive• Intermediate• Rapid

The procedures are discussed in detail in Resource Directed Measures for protection of water resources:Methodology for the Determination of the Ecological Water Requirements for Estuaries. Version 2 (DWAF,2004). A summary of the procedures used for the Intermediate Ecological Reserve Determination forestuaries are illustrated in Figures 1 1 and 1.2 of this report. Based on the available information andexpertise, the study on the East Kleinemonde Estuary was conducted at the Intermediate ievel.

Assumptions and Limitations

The following assumptions and limitations must be taken into account when assessing the outcomes of thisstudy:

• The hydrological data were provided to the estuarine team by Prof D A Hughes of the Institute for WaterResearch. Confidence in these data sets was low because runoff data were not available for thecalibration of the simulated runoff scenarios.

• The accuracy of predicted Abiotic States for the East Kleinemonde Estuary and the occurrence of thesestates under Reference Conditions, Present State and Future Scenarios depends largely on theaccuracy of the simulated runoff data and the number of observed breaching and closing eventsrecorded during the study.

Criteria for the confidence limits attached to statements in this study are as follows:

Limit Degree of confidenceLow If no data were available for the estuary or similar estuaries (i.e. < 40%)Medium If limited data were available for the estuary or other similar estuaries (i.e. 40-80%)High If sufficient data were available for the estuary (i.e. > 80%)

Geographical boundaries

For the purposes of the Ecological Reserve determination for the East Kleinemonde Estuary, thegeographical boundaries are defined as follows (WGS84):

• Downstream boundary: Estuary mouth (33° 32' 23.76" S, 27 03' 00.32" E)

• Upstream boundary: Approximately 4 km upstream of the mouth (33° 31' 21.38" S, 27° 01' 27.53"E).

• Lateral boundaries: 5 m contour above MSL along the banks, a delineation that can be readilyreferenced from an ortho-photograph of the area.

in

Present Ecological Status {PES)

The Estuarine Health Index (EHI) scores allocated to the East Kleinemonde Estuary {PresentState) were:

VariableHydrologyHydrodynamics and mouth conditionWater qualityPhysical habitat alterationHabitat health scoreMicroalgaeMacrophytesInvertebratesFishBirdsBiotic Health ScoreEstuarine Health score

Weiqht %25252525

2020202020

Score95907885

8085909085

Weighted score24232021

871617

181817

8687

The Estuarine Health Index score for the East Kleinemonde Estuary, based on its Present State, is 87,translating into a Present Ecological Status of a B+ as indicated below:

Estuarine Health Index91-10076-9061-7541-6021-400-20

Present Ecological StatusABCDEF

General descriptionUnmodified, naturalLargely natural with few modificationsModerately modifiedLargely modifiedHighly degradedExtremely degraded

Although the Present Ecological Status of the East Kleinemonde Estuary is a high B, the system is on atrajectory of change downwards. At the specialist workshop it was noted that an increase in fishingpressure, nutrient input from the catchment and septic tanks, riparian developments, noise disturbance andloss of aquatic habitat due to boating are influencing the system negatively.

The Estuanne Importance scores allocated to the East Klemmonde Estuary Turpie (2002. 2004)r were asfollows:

Criterion

Estuary SizeZonal Rarity TypeHabitat DiversityBiodiversity ImportanceFunctional Importance

Weight

1510252525

Score

7010908460

Estuarine Importance Score

Weightedscore

111

23211570

The Functional Importance of the East Kleinemonde on a regional scale is estimated to be 60, sincesignificant amounts of organic material generated in the estuary during the closed phase are exported to thenearshore during the open phase. The overall Estuarine Importance Score, based on its Present State is70, thus indicating that the estuary is important, as indicated below:

Importance Score81-10061-800-60

DescriptionHiqhly important

ImportantOf low to average importance

IV

Recommended ecological category for East Kleinemonde Estuary

The recommended Ecological Reserve Category (ERC) represents the level of protection assigned to anestuary. In turn, it is again used to determine the Ecological Reserve. For estuaries, the first step is todetermine the 'minimum' Ecological Reserve Category of an estuary, based on its Present Ecological Status(PES). The relationship between Estuarine Health Index Score, Present Ecological Status and EcologicalReserve Category is set out below:

Estuarine HealthIndex91-100

76-90

61-7541-6021-400-20

Present EcologicalStatus

A

B

CDEF

Description

Unmodified, naturalLargely natural with fewmodificationsModerately modifiedLargely modifiedHighly degradedExtremely degraded

Ecological ReserveCategory

A

B

CD--

Note: Should the Present Status category of an estuary be either an E or F, recommendations must be made as to howthe status can be elevated to at least achieve a Category D (as indicated above).

The minimum Ecological Reserve Category is determined by the Present Ecological Status. The degree towhich the Ecological Category needs to be elevated above the Present Ecological Status depends on thelevel of importance and the level of protection or desired protection of a particular estuary (see below).

Current/desired protection statusand estuary importance

Protected area

Desired Protected Area

Highly important

Important

Of low to average importance

RecommendedEcological Reserve

Category

A or BAS*

PES + 1, minB

PES + 1, minC

PES, minD

Policy basis

Protected and desired protectedareas should be restored to andmaintained in the best possiblestate of healthHighly important estuaries shouldbe in an A or B classImportant estuaries should be inan A, B or C classThe remaining estuaries can beallowed to remain in a D class.

* BAS = Best Attainable State

The East Kleinemonde Estuary is being targeted as a Desired Protected Area by the C.A.P.E. EstuariesConservation Plan for the temperate areas of South Africa (Turpie and Clarke, 2007). According to theguidelines for assigning a recommended Ecological Reserve Category, the estuary should be classified as aCategory A or the Best Attainable State {BAS).

At the specialist workshop it was concluded that the changes currently contributing to the Present State ofthe estuary are related to flow reduction, fishing pressures, human disturbance around the estuary andnutrient loading from the catchment.

The East Kleinemonde Estuary is very vulnerable to non-flow related activities such as fishing, power boatingand nutrient loading. The present level of urban development around the estuary acts as a constraint andprevents the system from being rehabilitated to a Category A. Thus, the workshop concluded that therecommended ERC for the East Kleinemonde Estuary be a Category B, i.e. at least maintain the PresentEcological Status.

Quantification of Ecological Reserve Scenarios

A summary of the suite of future runoff scenarios, evaluated as part of this project, as well as the Referenceand Present flow scenarios (provided by Prof D A Hughes, Institute for Water Research, Rhodes University),is presented below.

Name

ReferencePresentFuture Scenario 1

Future Scenario 2

Future Scenario 3

Future Scenario 4

Description

ReferencePresent FlowsDam Development (excluding an increasein non-flow related anthropogenic activities)Off-channel intermittent abstraction{excluding an increase in non-flow relatedanthropogenic activities)Similar to Scenario 2, factoring in other non-flow related anthropogenic activities.Similar to Scenario 2, factoring in other non-flow related anthropogenic activities, butmitigating for the increase in waste waterand stormwater runoff

MAR (millionm3/annum)

2.8562.748

2.409

2.575

2.575

2.575

PercentageRetained

100.096.2

84.3

90.1

90.1

90.1

The Present State of development represents a situation that has 300 residential plots that are suppliedwith water from the Wellington Dam (capacity: 0.206 x 10b m3) supplemented by borehole water. TheWellington Dam is situated on a tributary of the East Kleinemonde River that draws from approximately9% of the total catchment area of the East Kleinemonde system.

Details on the four simulated Future Scenarios are as follows:

• Future Scenario 1: This comprises 1010 developed residential plots with the water supply originatingfrom a new dam to be constructed on the main river. The assumption is that the sub-catchmentfeeding the dam represents about 67% of the total catchment area with the capacity of the dambeing determined appropriately, given the patterns of inflow and the demand Based on this futurehousing development scenario, the maximum recommended percentage of the MAR impoundedincreases from approximately 4% (present) to almost 16%.

• Future Scenario 2: Development plans envisage 1010 developed residential plots with the watersupply originating from an off-channel reservoir fed by intermittent pumping from the main river ondemand from a suitable weir the size and construction of which is to be determined. The assumptionis that pumping will remove most of the water from the river during low flow periods but will have littleimpact on the short-duration higher flows that have most influence on estuary function. Evaporativeloss from a dam will be eliminated in this scenario.

• Future Scenario 3: Similar to Scenario 2, but also including all other non-flow related anthropogenicactivities associated with the new developments (e.g. increased fishing pressures, power boating,human disturbance, seepage from septic tanks, storm water runoff).

• Future Scenario 4: Similar to Scenario 3, but mitigating for the increase in municipal waste water andstorm water runoff from the new developments.

VI

The individual Estuarine Health Index (EHt) scores, as well as the corresponding Ecological ReserveCategory for the various scenarios, were calculated according to EH1 methodology and are shown in thefollowing table:

Variable

HydrologyHydrodynamics/mouth conditionWater qualityPhysical habitat alterationHabitat Health ScoreMicroalgaeMacrophytesInvertebratesFishBirdsBiotic Health Score

Weight

25252525502020202020

50

Estuarine Health index ScoreEcological Reserve Category (ERC)

Present

95907885

878085909085

8687

B

Future Runoff Scenario1

9380808585808185808282

83B

2

9385798586808380858583

84

B

39385647668656060605549

""" 58D

49385797671807070625756

64

C

Recommended ecological flow requirement for East Kleinemonde Estuary

The evaluation of the simulated runoff scenarios was used to derive the recommended Ecological FlowRequirement. The recommended Ecological Flow Requirement is defined as the runoff scenario (or a slightmodification thereof) that represents the highest reduction in river inflow that will still protect the aquaticecosystem of the estuary and keep it in the recommended ERC.

In evaluating Future Scenarios 1 and 2, the assumption was made that only river in-flow from the catchmentswill be reduced and that all additional non-flow related anthropogenic activities (e.g. increased fishing andbait collection, power boating, human disturbance, seepage from septic tanks, stormwater runoff) will not beconsidered. Future Scenario 3 represents the expected impact of flow reduction and additional non-flowrelated anthropogenic activities on the estuary if 1010 residential plots are developed in the estuarineenvirons. Scenario 4 represents the expected impact of flow reduction and additional non-flow relatedanthropogenic activities, but mitigating for the impact of nutrient loading as a result of seepage from septictanks and pollutants from storm water runoff.

Both Scenario 1 and Scenario 2 will maintain the East Kleinemonde in the recommended ERC, as there isvery little reduction in runoff and impact on the estuarine ecosystem. Scenario 2 was selected as therecommended Ecological Flow Requirement because Scenario 1 (which includes an in-channel damdevelopment) represents a serious risk to migratory species (e.g. eels) that use the river as a conduit to theupper catchment. Dams act as permanent barriers to fish migration and negatively influence riverecosystems by changing the downstream flow regime.

VII

East Kleinemonde: Summary of flow distribution (mean monthly flows in m3 s1) under FutureScenario 2

99%ile

90%ile

80%ile

70%ile

60%ile

50%ile

40%ile

30%ile

20%ile

10%ile

1%ile

OCT

0.765

0.240

0.117

0.064

0.024

0.010

0.003

0.001

0.000

0.000

0.000

NOV

1.183

0.236

0.074

0.047

0,027

0.016

0.005

0.000

0.000

0.000

0.000

DEC

0.665

0.162

0.065

0.023

0.008

0.003

0.000

0.000

0.000

0.000

0.000

JAN

0.245

0.074

0.012

0.004

0.001

0.000

0.000

0.000

0.000

0.000

0,000

FEB

0.803

0.052

0,019

0.006

0.002

0.000

0.000

0.000

0.000

0.000

0.000

MAR

1.524

0.184

0.081

0.027

0.010

0.003

0.001

0.000

0.000

0.000

0.000

APR

1.023

0.205

0.064

0.043

0.025

0.003

0.001

0,000

0.000

0,000

0.000

MAY

2.702

0.152

0.051

0.019

0.007

0.001

0.000

0.000

0.000

0.000

0.000

JUN

1.127

0.200

0.039

0.010

0.004

0.001

0.000

0,000

0.000

0.000

0.000

JUL

0.931

0.113

0.025

0.009

0.003

0.001

0.000

0.000

0,000

0.000

0.000

AUG

0.958

0.103

0.037

0,017

0.008

0.001

0.000

0.000

0.000

0.000

0.000

SEP

1.513

0.230

0.065

0.029

0.010

0.005

0,003

0.000

0.000

0.000

0.000

When implementing the recommended ERC (Scenario 2) in future, the following should be noted:

The selection of Scenario 2 means that although the East Kleinemonde is a small temporarily open/closedestuary, it can accommodate the reduction in fluvial flow necessary to meet the requirements of futurehousing development in the area. However, it will not be able to support the additional non-flow relatedhuman disturbance pressures that wiil be associated with the planned residential developments. Thereforethe approval of any future residential developments should be conditional on the following mitigationmeasures being implemented:

• No consumptive use (e.g. fishing or bait collection) should be allowed in the East KleinemondeEstuary:

• No power boating on the East and West Kleinemonde estuaries (only canoes and electric motors tobe allowed);

• All new urban developments will have to be connected to a Waste Water Treatment Works toeliminate the risk of seepage from septic tanks entering the estuary;

• Storm water run-off from newly developed areas will have to be captured and diverted from thesystem to prevent hydrocarbons and other pollutants from entering the system.

In order to maintain the estuary in its present state, consumptive use (exploitation) of marine living resourcesneeds to be managed. Because the system is relatively small, there is no optimum zonation scheme that canaccommodate this requirement, e g. white steenbras occur predominantly below the road bridge in the sandyareas while other species occur above the bridge. Zoning to protect one fish species will make others morevulnerable, since it will lead to increased fishing pressure in other parts of the estuary. Serious concern wasalso raised over habitat destruction caused by bait collection since the areas where bait species occur arelimited. Thus, the only effective mitigation measure in response to increased development in the environs ofthe East Kleinmonde is to close it for all consumptive uses.

Power boating in small estuaries causes habitat destruction (mainly as a result of bank erosion from boatwakes), pollution {antifouling paints and oils), disturbs the feeding and breeding of birds, and significantlydisturbs fish (especially small fish in shallow areas). It is, therefore, recommended that power boating bebanned from both the East and West Kleinemonde as they are similar in size and closure of one is likely todouble the boating pressures on the adjacent system. Larger, permanently open estuaries such as thenearby Kowie and Kariega are much more resilient with respect to the impacts of power boating and aresafer systems to use by virtue of their size.

At present, septic tanks are used for the treatment of domestic wastewater (sewage) at Kleinemonde.Although the use of French drains and septic tanks, and absence of sewage treatment plants may beacceptable options for smaller communities, these options are usually not acceptable for larger humansettlements. The risk of impact on water resources, associated with spillages and seepage, increases

VIII

markedly with the increase in the number and density of housing developments. Adverse impacts associatedwith sewage spillages and seepage include eutrophication (e.g. excessive reed growth along the banks ofthe estuary) and human health risks (eg associated with contract recreation activities}. South Africa doesnot have clear guidelines on this matter, but internationally it has become common practice to provide acollecting system to communities (including coastal communities) with a service population greater thanabout 2 000 (RSA DWAF. 2004). It is therefore strongly recommended that any new residential developmentin the East Kleinemonde Estuary consider wastewater collection systems connected to either a conventionalexisting WWTW or an alternative treatment facility (e.g. artificial wetland).

Increased development (and an increase in hard surfaces) will also increase stormwater runoff into theestuary with likely increases of hydrocarbons, nutrients, turbidity and other pollutant loads. It is proposed thatfor any new development, the developer be made responsible for managing storm water run-off whereby, forexample, the storm water run-off from a new development is contained and treated at central points beforedischarge into the environment (e.g. Thesen Island Development, Knysna).

The West Kleinemonde Estuary is similar in size to the East Kleinemonde and would therefore also be veryvulnerable to increased urban development. This matter needs to be investigated before new developmentsin the area are approved. In future, RDM determinations should incorporate a regional assessmentcomponent to address the impact of development on adjacent systems.

IX